As one of the seniors from class D at Bellmare Girls Academy, you and the rest of your classmates are scheduled for a recreational field trip. As your first trip of the spring semester, it gives you the opportunity to get out of the stuffy school grounds and enjoy yourself alongside your friends and fellow students.

On the way, rocked by the steady rumbling of the bus over asphalt, you find yourself feeling very tired. What intends to be a short power nap turns out to be for the worst, because you will soon find yourself part of one of the unlucky classes subjected to the Battle Readiness and Survival Program.